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Monster Slime Cake

Woh, I always feel like somebody's watching me.


  • Cake
  • 350 g (121/2 oz/21/3 cups) plain (all-purpose) flour
  • 450 g (1 lb) caster (superfine) sugar
  • 100 g (31/2 oz) cocoa powder
  • 4 tbsp food safe activated charcoal powder
  • 1 teaspoon bicarbonate of soda (baking soda)
  • 1 teaspoon fine salt
  • 350 g (121/2 oz) unsalted butter, softened
  • 4 large eggs, at room temperature
  • 350 ml (12 fl oz) full-cream (whole) milk
  • Slime Frosting
  • 1 batch vanilla Swiss meringue buttercream frosting
  • 1 tsp pineapple flavouring
  • 5 drops green food gel
  • 5 drops yellow food gel
  • Black Frosting
  • 1 batch Chocolate Swiss meringue buttercream frosting
  • 3 tbsp food safe activated charcoal powder
  • Slime Ganache
  • 500g white chocolate
  • 250ml thickened/whipping cream
  • 1 tsp pineapple flavouring
  • 5 drops green food gel
  • 5 drops yellow food gel
  • Decorations
  • 100g Small eye ball candy decorations
  • 100g Large eye ball candy decorations


  1. Slime Ganache
  2. Add white chocolate and cream into a large microwave safe bowl. Microwave for 20 seconds at a time, mixing each time until smooth. Add green and yellow food gel. Whisk until evenly coloured. Add pineapple flavouring and whisk until well combined. Set aside to set at room temperature.
  3. Slime Frosting
  4. To make lime frosting add green and yellow food gel along with the pineapple flavouring to the frosting and mix until well combined.
  5. Black Frosting
  6. To make the black frosting add activated charcoal to the chocolate frosting and mix until well combined.
  7. Cake
  8. Please note: to make the four-layered cake in this recipe you’ll need to make 1.5 times the cake mixture. The frosting, ganache decorations will be enough.
  9. Preheat a fan-forced oven to 160°C (320°F) or a conventional oven to 180°C (350°F). Spray two 18 cm (7 in) cake tins with oil spray and line the bottoms with baking paper. Set aside.
  10. Add the flour, sugar, cocoa powder, charcoal powder, bicarbonate of soda and salt to a large mixing bowl and mix with a hand mixer until well combined.
  11. Next, add the softened butter and mix on low speed until the batter reaches a crumbly, sand-like texture.
  12. Add the eggs and milk and mix again on low speed until all the dry ingredients are incorporated. Scrape down the side of the bowl and mix for another 20 seconds. It’s at this point that you can add any additional flavourings or food-gel colourings to the batter.
  13. Divide the cake mixture between the two tins. I find that using an ice-cream scoop makes it easy to distribute the batter evenly, ensuring that all three cakes will bake at the same rate.
  14. Bake for 50–60 minutes, or until a toothpick inserted in the middle a cake comes out clean. If the toothpick is coated with wet batter, continue baking, for 10 minutes at a time, until fully baked.
  15. Allow the cakes to cool to room temperature in the tins, then chill them in the fridge overnight. Chilling your cakes overnight makes them easier to trim and decorate, so I always bake my cakes the day before I decorate them.
  16. To trim your chilled cakes, use a cake leveller or large serrated knife to carefully trim the crust off the top of each cake before you trim each cake in half. You’ll end up with 4 layers of cake.
  17. To crumb coat your cake, add a dab of frosting onto a black 8” cake board or flat serving plate. Use a small offset spatula to spread the frosting around before adding the first cake layer. Gently press down the centre of the cake layer to make sure it’s stuck to the frosting underneath.
  18. Add slime frosting to a piping bag and frost a ring around the top of the cake. Fill the centre with the set slime ganache and spread with an offset spatula before you add the next layer of cake. Repeat with the remaining layers.
  19. Add more frosting around and top and sides of the cake. Use the small spatula to smoothen out the top and sides of the cake, taking care to fill in any gaps in between each layer of cake.
  20. Use a cake scraper (otherwise known as a bench scraper) to smoothen out the frosting on the sides and top. Get it as neat as you can. This should just be a neat, thin layer of frosting which is aimed at trapping any cake crumbs so that random bits of cake crumbs don’t show up on the final layer of frosting. Chill for 2 hours or overnight.
  21. Add the black frosting to the chilled cake the same way you did with the slime frosting. Smoothen out the sides and top using the cake scraper. Chill for 1 hour.
  22. To prepare the slime ganache for piping, microwave for 10 seconds at a time, whisking each time until the mixture becomes runny enough to drip, but not thin enough that it becomes see through.
  23. Add the slime ganache to a squeeze bottle or piping bag and and drizzle it over the top of the cake allowing it to drip over the sides of the cake. Set the rest of the slime ganache in the fridge to set while you add the eye candy decorations.
  24. Once the ganache has set a little and it’s no longer runny but at a spreadable stage, pile it on top of the cake.